71665039 has 4 divisors (see below), whose sum is σ = 71695624. Its totient is φ = 71634456.

The previous prime is 71665021. The next prime is 71665051. The reversal of 71665039 is 93056617.

71665039 is nontrivially palindromic in base 9.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93056617 = 3079 ⋅30223.

It is a cyclic number.

It is not a de Polignac number, because 71665039 - 2¹⁷ = 71533967 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 71664989 and 71665007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71665019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11457 + ... + 16570.

It is an arithmetic number, because the mean of its divisors is an integer number (17923906).

Almost surely, 2^71665039 is an apocalyptic number.

71665039 is a deficient number, since it is larger than the sum of its proper divisors (30585).

71665039 is a wasteful number, since it uses less digits than its factorization.

71665039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30584.

The product of its (nonzero) digits is 34020, while the sum is 37.

The square root of 71665039 is about 8465.5205982857. The cubic root of 71665039 is about 415.3706255031.

The spelling of 71665039 in words is "seventy-one million, six hundred sixty-five thousand, thirty-nine".